| Mcgrigors LLP | | 2006 |
| Mcguinness Capital Ltd | Real estate | 2020 |
| Mcguinness Propco Ltd | Real estate | 2020 |
| MCH Plumbing and Heating Ltd | Construction | 2024 |
| MCH Property & Estates Ltd | Construction | 2026 |
| MCH Solutions Limited | Construction | 2020 |
| Mchughes & Associates | | 1993 |
| Mcii LLP | | 2014 |
| Mcil Scottish Limited Partnership | | 2024 |
| Mcinnes Limited | Real estate | 2021 |
| Mcintosh Mccann Limited | Professional & scientific | 2017 |
| Mciver Properties Limited | Hospitality | 2022 |
| Mckai Ltd | Information & communication | 2025 |
| Mckays Waste Management Limited | Water & waste | 2019 |
| Mckenna Joinery and Construction Limited | Construction | 2024 |
| Mckenzie Accountancy Limited | Professional & scientific | 2026 |
| Mckenzie Clay Limited | Professional & scientific | 2015 |
| Mckenzie Marketing Ltd | Professional & scientific | 2020 |
| Mckenzie Potter Ltd | Real estate | 2025 |
| Mckillop Radiology & Teaching Limited | Education | 2010 |
| Mckinley & Coutts LLP | | 2025 |
| Mckinley Medical Services Limited | Health & social care | 2011 |
| Mckinney Investments Limited | Financial services | 2017 |
| Mcknight Martin (Leeds 1) Ltd | Real estate | 2023 |
| Mcknight Martin (Leeds 2) Ltd | Real estate | 2023 |
| Mcknight Martin Investments (Frederick Street) Limited | Real estate | 2019 |
| Mcknight Martin Investments Limited | Real estate | 2018 |
| Mcknight Martin Property Group Limited | Real estate | 2024 |
| MCL Electrical Limited | Administrative & support | 2016 |
| MCL Estates (Ventures) Limited | Real estate | 2018 |
| MCL Estates Limited | Real estate | 2014 |
| MCL Recipe Ltd | Wholesale & retail | 2019 |
| Mclaren of Broxburn Limited | Real estate | 1968 |
| Mclaren of Craig Plant and Contracting Limited | Construction | 2015 |
| Mclaren Ross Hair Studio Limited | Other services | 2015 |
| Mclaren Tree Surgery Ltd | Administrative & support | 2019 |
| Mclarty Capital Partners UK SME Founder LP | | 2017 |
| Mclarty Capital Partners UK SME GP LLP | | 2017 |
| Mclaughlin Crolla LLP | | 2009 |
| Mclayer Ltd | Construction | 2023 |
| Mclean & Davie Ltd | Real estate | 2025 |
| Mclean & Partners Wealth Management Ltd | Financial services | 2007 |
| Mclean Cabs | | 1998 |
| Mclean CT Consulting Ltd | Health & social care | 2012 |
| Mclean Group Limited | Construction | 2017 |
| Mclean Properties Limited | Real estate | 2015 |
| Mcleay Investments Limited | Financial services | 2013 |
| Mclellan Investments Limited | Real estate | 2017 |
| Mclennan Capital Limited | Professional & scientific | 2025 |
| Mclennan Family Holdings Limited | Real estate | 2025 |
| Mclennan Legal Services Limited | Professional & scientific | 2018 |
| Mcleod & Mcleod Marine Supplies | | 1992 |
| Mcleod Consulting Limited | Administrative & support | 2022 |
| Mcleod Property Letting Ltd | Real estate | 2024 |
| Mclure Custom Guitars Ltd | Manufacturing | 2023 |
| MCM Edinburgh Ltd | Real estate | 2015 |
| MCM Financial Limited | Financial services | 2015 |
| Mcmahon IT Consulting Limited | Information & communication | 2013 |
| Mcmahon Mortgage & Protection Ltd | Financial services | 2024 |
| Mcmarkham LLP | | 2023 |
| Mcmasri Ltd | Extraterritorial | 2022 |
| Mcmaster Electrical Services Limited | Manufacturing | 2006 |
| Mcmichael Concepts Limited | Education | 2013 |
| Mcmunch Ltd | Hospitality | 2025 |
| Mcmusic Ltd | Other services | 2020 |
| Mcnally & Co | | 1992 |
| Mcnally Healthcare Ltd | Professional & scientific | 2019 |
| Mcnamara Plastering Ltd | Construction | 2023 |
| Mcneil and Greenan Ltd | Hospitality | 2011 |
| Mcneil Trust Limited | Professional & scientific | 1946 |
| Mcneill, Maguire and Mccreath Surveyors Limited | Professional & scientific | 2005 |
| MCP Annual Secondary Program Annex, L.P. | | 2012 |
| MCP Annual Secondary Program II, L.P. | | 2014 |
| MCP Annual Secondary Program, L.P. | | 2012 |
| MCP Commercial Limited | Professional & scientific | 2020 |
| MCP Investor Two Limited Co-Invest L.P. | | 2013 |
| MCP Opportunity Secondary Program III, L.P. | | 2015 |
| MCP Opportunity Secondary Program IV Founder, L.P. | | 2017 |
| MCP Opportunity Secondary Program IV, L.P. | | 2017 |
| MCP Private Capital Fund I CI GP Limited | Administrative & support | 2012 |
| MCP Private Capital Fund I CI LP | | 2012 |
| Mcpartland Decorators Limited | Construction | 2017 |
| Mcpherson & Smith Limited | Health & social care | 1995 |
| Mcpherson Optometry Limited | Wholesale & retail | 2022 |
| Mcquaker & Co Limited | Professional & scientific | 2014 |
| Mcquarrie Law Consultancy Limited | Professional & scientific | 2015 |
| Mcquatt+Co Ltd | Real estate | 2013 |
| Mcqueen PS Ltd | Real estate | 2011 |
| Mcqueen Residential Properties Limited | Real estate | 2016 |
| Mcritchie Games Ltd | Information & communication | 2024 |
| Mcrobb Display Limited | Administrative & support | 2005 |
| Mcrobb EOT Limited | Extraterritorial | 2024 |
| MCS Consulting Limited | Information & communication | 2010 |
| MCS Stair and Property Cleaning Ltd | Administrative & support | 2013 |
| Mcschef Ventures Limited | Real estate | 2024 |
| Mcshane Enterprises & Co | | 1993 |
| Mcstuart & Associates | | 1992 |
| MCT Associates Limited | Administrative & support | 2021 |
| Mctaggart Properties Limited | Real estate | 2015 |
| Mctavish, Ramsay & Company Limited | Manufacturing | 1953 |